Method of bending



UNITED sTATEs PATENT oEEicE.

THOS. BLANCHARD, OF BOSTON, IVIASSACHUSETTS.

METHOD OF BENDING WOOD.

Specification of Letters Patent No. 15,944, dated October 21, 1856.

To all 'whom t may concern Be it known that I, THos. BLANCHARD, ofBoston, in the county of Suffolk and State of Massachusetts, haveinvented a new and Improved Method of Bending Timber, of which thefollowing is a full, clear, and exact description, reference being hadto the annexed drawings, making part of this specification, in whichyFigure l is a plan showing the timber confined in the machinepreparatory to bending; Fig. 2, a plan showing the timber after thebending is completed; Fig. 3, a section upon the line A A of Fig. 1;Fig. 4L, a section upon the line B B of Fig. l; Figs. 5, 6, `7, 8, 9,10, 11, l2, 13, 14, details which will be referred to hereafter.

My invention has for its object the bending of timber both of small andlarge dimensions, and consists in submitting it to pressure upon everyside, and upon the ends during the operation of bending, by which meansit is prevented from swelling, bursting or cracking at the point bent,as would otherwise be theca-se were the timber bent without being thusconfined.

To enable others skilled in the art to understand my invention I willproceed to describe the manner in which I have carried it out, and theconstruction of my machine.

C, 11, is the bed piece or foundation of the machine, upon which aresecured the operating parts.

D, Fig. `12, is the bending lever, which turns upon the center E risingfrom the bed piece.

F is an abutment rising from the bending lever D against which the endof the timber is pressed bythe bending screw G, which bearsupon theclamping piece I, the end of the timber being firmly and securely heldto the bending lever by `the pressure between the abutment F and theclamping piece I as seen in Figs. 1 `and 2. `Immedi-` ately back of theportion thus held the timber is slightly confined in a trough or box forthe purpose as before mentioned of preventing it from swelling orbursting. This is accomplished in the following manner. The bottomsurface of the timber rests upon the bed piece C or upon the plate Yinterposed between it and the bed piece. Upon one side it is supportedby the truss beam K seen in perspective in Fig. 8, and

upon the opposite side by the back support` L (Fig. 9). Attached to thisback supporting plate are two sliding clamps M which pass throughmortises in the bed piece (Fig. 4) and serve whenldrawn up to the bedpiece by the keysa to hold the back support rigidly in place, andcompress the timber between it and truss beam.

The timber is confined and compressed in a vert-ical direction by thefollowing means: N (Fig. 10) is a metallic plate which I call thestraight follower (seen in plan in Fig. l and in red outline in Fig. 2),which is `placed upon the upper surface of the timber. c are uprightrods which rise from the surface of the straight follower and enter theslots in the hooked uprights cl attached to the top edge of the backsupport L. The follower N is thus prevented from being drawnlongitudinally out of placeit is forced down upon the timber by thewedge shaped keys b, whereby the latter is compressed between it and thebed piece of the machine. `The timber is thus held compressed in atrough formed by the bed piece C or t-he interposing plate Y, thestraightfollower N, the truss beam K, and the block support L. Out ofthis trough it is drawn as it is bent into a circular mold which will bepresently explained. The bed piece, straight follower and back supportremain stationary, while the timber is withdrawn, but t-he truss beamfollows on with the timber as will be hereafter more fully described.

lThe circular mold which receives the timber as it is drawn out of thestraight trough is constructed as follows: It is evident that the curveof this mold must be struck from the center of motion of the bendinglever D, and as it is necessary to retain the pressure upon the timberfor some ho-urs after the bending is completed, in order to prevent itfrom returning to its former shape or from bursting, or cracking, it isdesirable that while this circular mold is capable of being so adaptedto the bending lever as to partake of all its motions it Should at thesame time be so constructed that it may be removed from the machine withthe timber without relieving the latter from the compression to which itis subjected, this is accomplished in the following manner: The bottomand one side of the circular mold are formed by what I denominate themold O seen in perspective in Fig. 6 and in section `in Fig. 3. Thismold is adapt-ed to a recess P formed for the purpose in thebendinglever D, and is furthermore secured thereto by a pin attached to themold which enters the hole g in the bending lever. When this mold is inplace, the timber placed in the machine ready for the bending operationis slightly entered int-o one end of the mold O as at Fig. l. Thecircular follower Q seen in red in Fig. 2, and in perspective in Fig. 7is then placed upon the timber upon which it is confined by the wedgekeys m driven beneath the hooks a.

I have now described the means by which the timberl is confined andprevented from cracking and splitting upon every side eX- cept upon theoutside or convex part of the bend; this portion of the timber isconfined and prevented from bursting out as it is bent by the followingmeans: R (Fig. 13) is a chain or strap which is made to embrace thetimber upon the outside as seen in Fig. 2. This strap or chain isflexible, and may be made of iron or of steel. 29 and g are returns atright angles to the strap, which.

pass over the ends of the timber and against which the upsetting or endpressure is made to bear. S is the clamping screw; the end of whichbears against a block t, this block pivots around the point u andcarries the roller w which by the operation of the screw S is forcedagainst the truss beam K; this latter while it is held up tightlyagainst the timber is thus permitted to slide past the roller as thetimber is drawn out of the machine. V, T, Y, X-V, T, Y, X, is a train ofgear wheels actuated by any sufIicientpower and giving motion to a shaftZ by the revolution of which through a rope or chain the bending leveris set in motion. Any other efficient means may be employed for thepurposeof actuating this lever.

By the meansv above described the timber it confined on every side. andcompressed while being bent; this is necessary for all large timber toprevent it from cracking and bursting, but it is absolutely essentialfor all timber small as well as large that it be compressed upon theends previous to the commencing of the operation or that it be notallowed to elongate upon the outside; this I effect in the bending oftimber of moderate size in the following manner: The timber is cut of alength just to fit between the return 79, g, of the strap Rf Thefollower or plunger A2 isthen caused to rest against the end of thetimber, the return g of the strap R interposing between the two; asufficient amount of end pressure is then put upon the timber by theupsetting or beam screw B2, which works in the truss beam K, the otherend of the timber being held by the clamping piece I. For most lightwork and for nearly all small articles this upsetting `or end pressureis all that is necessary to enable the wood to be bent to any requiredcurve; among such articles may be enumerated plow handles, fellies ofwheels, and the different parts of furniture.

Where ships knees and other heavy timber are to be bent it becomesnecessary in addition to the end pressure to submit the wood to sidepressure in the manner already described, otherwise there is danger thatit will swell and crack during the bending process, by which itsintegrity and strength are `greatly impaired, if indeed it'be notrendered useless.

Operation-The timber having been squared or brought into the requiredform is cut of a length that shall just fit into the strap R; it is thenplaced upon the bed piece as seen in Fig. 1, one end o-f it beingclamped to the bending lever between the abutment F and the clampingpiece I operated by the screw G. The mold O is then inserted in therecess in the lever D one end of it just entering beneath the timber atthe curved follower Q is placed upon the timber and keyed down by thekeys m as already described; the back support I, is then placed behindt-he timber it being made to enter in between the mold and the curvedfollower Q as seen in do-tted line, in Fig. l. That no considerableportion of the timber may be left unsupported the back support is drawnup to the timber by the keys a which pass through the sliding clamps Mprojecting from its lower edge and serve to hold it to the bed piece.The straight follower il which covers the timber is so made as to adaptit to the curved follower Q at t-he point y2, that the timber may at nomoment be relieved from pressure as it is drawn from the straightfollower and enters beneath the curved follower Q. To the other side ofthe timber is applied the truss beam K which unlike the other sidesupports of the timber is not made fast to the bed piece, but moves withthe timber as the bending proceeds; the truss beam is made to bear uponthe timber by the key and also by the clamp screw S, the roller Wpermitting the truss beam to move freely along with the timber. Theplunger A2, is now laid in as seen in Figs. l and 2 and by means of theupsetting screw B2, is made to bear against t-he end of the timber withthe required force.

Upon the outside of the strap R are projections C2, D2, which entercorresponding recesses in the clamping piece I and truss beam K by whichmeans not only is the timber forced to move with the bending lever D butthe truss bea-m and upsetting screw re caused to follow and move withthe tim- In bending heavy timber and where great strength is required astrong flat chain may be employed to surround the outside of the timber.This may be used either in conjunction with the strap R or it may beemployed alone; in such case, as the chain cannot yield it is evidentthat the outside of the timber as well as the inside will be compressed,unless some means be resorted to to relieve the end pressure as thebending proceeds, this may be effected by turning back the upsettingscrew, by hand or by self acting machinery actuated by the motion of thebending lever. To facilitate this operation I have adopted thearrangement represented in Fig. 14, in which'H is the timber to be bent;A3, a metallic plunger which receives the pressure of the upsettingscrew B3, this plunger passes through the return g of the strap whichencircles the timber and bears upon t-he metallic follower r which`rests against the end of the timber. Outside of the interior strap, isa secondary strap or chain S2, which is secured, Ias before eX- plainedof the strap R to the beam K and clam-ping piece I. As now the bendingproceeds, and it becomes necessary to permit the timber to elongate, toprevent the compression and crippling of the outer surface, the endpressure is gradually relieved by relaxing the screw B3, and is thusprevented from increasing to an injurious or useless degree.

The parts being arranged as above described, motion is communicated tothe lever D around its center E by the means described or in any othersuitable manner, and this lever is brought into the position seen inFig. 2, the timber being gradually bent and drawn out of thestraight boxin which it was first confined and transferred to the circular mold O inwhich it still remains clamped. It is now necessary that the timberremain compressed and confined for several hours and in order that themachine may be used for-the purpose of bending another stick the benttimber is removed in the following manner from the machine: H2, is a barhaving hooks upon its ends, which are made to enter holes or eyes in thereturns p and g of the strap R. The timber is thus prevented fromspringing back when it is relieved from the end pressure, and it maythen with the parts in which it is confined (F ig. 5) be removed fromthe machine.

Instead of one bending lever as shown in Figs. l and 2 there may be twolevers turning on the same center shaft, and standing in oppositedirections. The timber must be placed with the center of the curveagainst the center of the mold and be there made fast by the fasteningscr-ew or key. These levers may be drawn around by a chain or ropeattached at the outer end of each lever, and drawn toward each other byone windlass. In this case there must be an upsetting screw or key ateach end of the timber, and two truss beams with their fixtures, alsotwo bending chains, but only one inside strap.

On the 18th December, 1849, Letters Patent of the United States weregranted to me for a method of bending fibrous materials by compressingthe ends of the stick. This I have found to be suiiicient for thepurposeof bending sticks of small size. ever discovered that in order tobend sticks of larger dimension for ship timber or other purposes, it isnecessary not only to submit it to end compression, but also to confineit upon every side to prevent it from bursting out laterally.

I do not therefore now claim submitting the timber to compression uponits ends, but

That I claim as my invention and 4desire to secure by Letters Patentis- 1. Subjecting the timber to pressure upon all sides and containingthe same while it is being transferred from the straight trough to thecurved mold as set forth.

2. The within described machine for the purpose of bending timberconsisting essentially of the following elements or their equivalents incombination: 1st, the bending lever; 2d, the device for compressing thetimber while it is being bent; 3d, the curved mold in which the pressureis continued and in which the timber is removed from the machine afterthe bending operation is completed. i

THOMAS BLANCHARD.

Witnesses:

SAM. COOPER, THos. R. ROACH.

